I can't stress enough the importance of working weight training into your routine!! You're on the right track!!
Start small, and gradually move up to heavier weights when it gets too easy.
Do you feel like you might want to try a workout video? If so, I can recommend some for you that mix cardio and weights into one workout. They will help you with your form, guide you through abs, and motivate you. And, they can be FUN!!
Let me know if I can help...
Carole